The invention herein refers to a retainer, i.e. an element of temporary retention for a plastic injection mold slide, a retainer which appropriately positioned in the said slide, allows the connection of the same to the corresponding track, keeping it in a stable position, particularly whilst opening the mold.
The object of the invention is to achieve a retainer capable of withstanding slides of considerable weight, maintaining them completely immobile.
As we know, in the field of injection molds the slides run along a track, the slides having holes which accommodate guides attached to the other piece of the mold, in such a way that during the maneuver of opening the said mold the aforementioned guides separate completely from the slides, which must remain in a stable position on the corresponding tracks once the guides have departed from them.
To achieve this effect, several solutions exist, such as one where the connection of the slide to the track is achieved by means of magnets, a solution which is particularly ideal when dealing with small slides, and another where retainers are used in the form of pegs which, when fixed to the slide, operate on a pivot which is duly connected to the track, causing the required retention.
In practice, these retainers take the form of a type of pincers, having two articulated arms, between which there is an open, circular housing, which operates in conjunction with the aforementioned pivot, its arms separating to allow to entrance of the pivot in the housing, bearing the pressure of the interior springs. This structurally very complex and consequently very expensive solution, implies a very significant volume, which makes it necessary to have a rather complex mechanism on the track base, to house the retainer, which also directly influences the cost of the equipment, as well as causing functional inaccuracies.
In an effort to avoid this problem, the same applicant is the holder of Utility Model U8701679, in which a retainer is described for injection mold slides and plates which takes the shape of a simple, single, flat piece of flexible material, preferably tempered steel, in which there is a small nucleus on one end, which has an orifice with a countersunk opening, in which enters a single screw to connect the aforementioned piece to the slide, a nucleus from which protrude two flexible, parallel arms which take the shape of a type of peg or clip connecting the retainer to the pivot incorporated in the track.
This solution, may only require minimal space for installing the retainer and, furthermore, allows for quick and simple installation, as with the aforementioned system in the form of pincers, it is only viable for relatively lightweight slides, of up to around 20 kg, so for heavier weights it is necessary to use several retainers superposed or adequately distributed to carry out their function.
The retainer proposed by the invention completely solves the aforementioned problem, enabling large slides to be blocked, withstanding a force of over 100 kg, i.e. five times more than conventional retainers.
In order to do this, the retainer of the proposed invention specifically uses a slide with a housing which is at an angle in relation to the direction of movement of a guide at the same angle, so that the movement of the guide in the hollow of the slide at the same time causes the movement of the slide on the corresponding track.
Thus, with this basic structure, the retainer which the invention proposes takes the form of a rod, housed in an orifice of the slide, perpendicular to the track, and with the movement of the slide, comes into line with a blind orifice drilled into the aforementioned track, this taking place specifically at the moment in which the slide is free of the guide pulling it.
The aforementioned rod has one end with a shorter diameter, the opposite end to the track, on which there is a spring which is constantly pushing the rod against the track, while its upper end has a transversal pivot which is operated by a rocker arm which is fitted in a way that it swivels on a support implanted and fixed to the slide, the rocker arm which, on the opposite end to that which operates on the aforementioned pivot, has a pulley wheel which by the effect of the aforementioned spring also tends to protrude into the interior of the slide housing and, consequently colliding with the active line of the guide, when the said guide is located inside the aforementioned housing.
In this way, while the guide is acting on the slide, the rod is retracted or inoperative, and when the guide leaves the slide support and leaves the rocker arm free, at the moment when the retaining rod is in line with the shallow orifice in the track, the spring causes the axial projection of the said rod, its entrance into the aforementioned blind orifice and the consequent stoppage of the slide.